3X38FTR Datasheet, PDF (30/64 Pages) Agere Systems – OCTAL-FET (Fast Ethernet Transceiver) for 10Base-T/100Base-TX/FX

3X38FTR 208-Pin SQFP
OCTAL-FET for 10Base-T/100Base-TX/FX
Preliminary Data Sheet
September 2000
Functional Description (continued)
Receive Path
Receive data and control information are signaled in
ten bit segments. These ten bit boundaries are delim-
ited by the SYNC signal. The connected MAC should
generate these SYNC pulses every ten clocks. In
100 Mbits/s mode, each segment represents a new
byte of data. In 10 Mbits/s mode, each segment is
repeated ten times, so every ten segments represents
a new byte of data.
The receive sequence contains all of the information
found on the standard MII receive path.
Out-of-Band Signaling
During an interframe gap, bit RXD5 indicates the valid-
ity of the upper nibble of the last byte of data of the pre-
vious frame. Bit RXD0 indicates an error detected by
the PHY in the previous frame. Both of these bits will be
valid in the segment immediately following a frame, and
will remain valid until the first data segment of the next
frame.
Transmit Data Path
Transmit data and control information are signaled in
ten bit segments similar to the receive path. These ten
bit boundaries are delimited by the SYNC signal. The
connected MAC should generate these SYNC pulses
every ten clocks. In 100 Mbits/s mode, each new seg-
ment represents a new byte of data. In 10 Mbits/s
mode, each segment is repeated ten times; therefore,
every ten segments represents a new byte of data. The
PHY can sample one of every ten segments.
Collision Detection
The PHY does not directly indicate that a collision has
occurred. It is left up to the MAC to detect the assertion
of both CRS and TXEN.
Table 10. Receive Data/Status Encoding
CRS RX_DV RXD0
X
0 Rcvr error
in the
previous
frame
X
1
RXD1
Speed:
0=
10 Mbits/s
1=
100 Mbits/s
RXD2
RXD3
RXD4
RXD5
Duplex:
Link:
Jabber: Upper nibble
0 = half 0 = no link
0 = OK
0 = invalid
1 = full 1 = good link 1 = detected 1 = valid
One Data Byte (two MII nibbles)
RXD6
False carrier:
0 = OK
1 = detected
RXD7
1
1
2
3
4
5
6
7
8
9
10
11
SMII_CLK
SYNC
TXD
TXER
TXEN
TXD0
TXD1
TXD2
TXD3
TXD4
TXD5
TXD6
TXD7
Figure 11. Transmit Sequence Diagram
5-7508(F).r1
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Lucent Technologies Inc.